As for a mechanism which locks the lid turnably supported in the case in the closed position, there is conventionally used the push-push mechanism. The push-push mechanism is formed by a striker provided in one of either the lid or the case, and a locking device provided in the other of either the lid or the case. The striker is pushed into the locking device to engage with each other, and the striker is pushed into the locking device again to disengage from each other so as to facilitate an opening/closing operation of the lid (for example, Patent Document 1). However, in a case of being applied to a storage case (including a glove box) and the like, due to a deceleration or a collision of an automobile, a predetermined acceleration is applied to the case, the lid is pushed to the case by an inertia force, and the push-push mechanism releases the locking so as to have a risk that the lid opens unintentionally. In regards to this problem, there is a safety device in which a lock pin device displaced in response to the predetermined acceleration (the inertia force) is provided in the case, and a locking groove is provided in the lid, and when an acceleration is applied to the case, the displaced lock pin device is locked in the locking groove so as to prevent the lid from opening (for example, Patent Document 2).